pinging issues

[JayBo]

I have a question about my tune. Seems as though ever since I've had one my truck would ping pretty bad, no matter which octane I used.
Well now, the last few days it's been pinging like crazy, and yesterday it was horrible. It's not just momentary, or at a certain rpm or anything like that, it does it from idle to WOT, and it does it BAAAD now. I've tried different brands of gas, changing the fuel filter, etc.. I have not changed the plugs yet or wires, but that's in the near future.
Last night, it was doing it so horribly that I just stopped driving and bought some octane boost. Well believe it or not, the pinging almost went completely away. Now is that saying that there is too much timing in the tune, or what? I've heard that when the engine predetonates like that the knock sensors will retard the timing therefore decreasing power. Is this correct? It sure feels alot weaker when its rattling like it has been.

This was the email I sent allen, I just wanted to see if I got any other opinions.
Thanx

[chrisj6]

I really think that '02 PCM will help you out alot, I had alot of the same problems with my '99 PCM before I switched. The '99 PCM can't tolerate as much timing it seems as the '02 can.

Chris

[COWL327]

I agree chris Ive seen more people with 99-01 pcm problems than any other.Is your maf descreened,that seems to a hangup no matter what year

[chrisj6]

Actually it would be the 99-00 PCMs that have the problems, the 01-02 are the same service #, with 411 being the last 4 digits. I got an '01 when Allen told me they were the same part #.

I definately agree on the descreened MAF though, that did help out a bit on the pinging problem when I put a screened one back in.

Chris

[JayBo]

I put the screen back in my MAF because of a previous post I made some time back and it helped some. I didn't reset the PCM though, should I do that? It's just gotten progressively worse especially in the last few weeks. It feels really weak when its pinging like this. I don't know if its a mental thing, or if it actually is weaker.

[COWL327]

Yes Reset the pcm,I did that for my 160 thermostat and Ill do it when I get my new MAF with screen

[JayBo]

SO pretty much I need a newer PCM hmmm? Nobody thinks there is too much timing in there, or its running lean?

[BlenderWizard]

Originally posted by JayBo@Oct 31 2005, 02:01 PM
SO pretty much I need a newer PCM hmmm? Nobody thinks there is too much timing in there, or its running lean?

I know I may be a little late, but you might try using some GM Top Engine Cleaner. If there are carbon deposits on your valves or pistons, they will "soak up" some fuel that will remain in the combustion chamber and cause premature detonation (or pinging). I used it in mine, and it sure did help mine a lot.

On a side note, "pinging" sure is a hard word for me to say. It ranks right up there with "mirror" and "horror"

[JayBo]

So where do you get this stuff? I'll try a can of that and change the plugs. The engine is getting really close to 100K and I think it's about time to start tuning it up.

I noticed the other morning that it smoked a little when I started it up first time of the day.

[BlenderWizard]

You can get it at a GM dealer service center; it's about $6 a can, Your truck will smoke like a chimney when you do it, and you'll probably need someone inside the truck to keep the truck at about 1000 RPM when you do it.